Aqueous Inkjet Ink Composition for Non-Absorbent Substrate Adhesion

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Solution Overview

Problem

Aqueous inkjet inks struggle to produce high-quality, durable images on non-absorbent printing substrates due to poor ink fixation and bleeding, especially when applied on low-absorption materials like plastic foils, and they are not stable at elevated temperatures.

Innovation Solution

An aqueous inkjet ink composition comprising a low concentration of calcium salt as a fixing agent, a polyurethane binder with low acid value, a dispersing agent with low acid value, and a pigment, which adheres well to non-absorbent substrates and maintains stability at elevated temperatures, allowing for high-quality, wipe-resistant printing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If aqueous inkjet ink is applied directly onto non-absorbent printing substrates like plastic foil, then the printing process is simple, but the printed image is prone to smearing and exhibits poor adhesion

Engineering Contradiction:
Improveprinting process simplicityVSAvoidink fixation and adhesion
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The inkjet ink contains pre-formulated binding agents (polyurethane dispersion, acrylic polymer) and fixing agents (calcium salts, zinc salts) that are applied together with the pigment in a single printing step. These components work together to ensure proper adhesion to non-absorbent substrates without requiring a separate primer application, thus maintaining process simplicity while improving ink fixation reliability

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The inkjet ink is formulated as a composite system combining pigment particles, binding agents (polyurethane dispersion, acrylic polymer), fixing agents (calcium salts, zinc salts), and surfactants. This composite formulation allows the ink to simultaneously achieve proper adhesion to non-absorbent substrates, prevent smearing, and maintain stability during printing operations without requiring separate primer and ink applications

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If further aqueous inkjet ink is printed on top of dried aqueous inkjet ink, then polychrome printing is achieved, but the subsequently applied ink may bleed and the printed image may be flawed

Engineering Contradiction:
Improvepolychrome printing capabilityVSAvoidprinted image quality
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The inkjet ink contains fixing agents (calcium salts, zinc salts) and binding agents that are applied together with the pigment in the first printing layer. These components create a stable, fixed base layer that prevents bleeding when subsequent ink layers are applied, enabling reliable polychrome printing while maintaining image quality

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The binding agents (polyurethane dispersion, acrylic polymer) and fixing agents (calcium salts, zinc salts) act as intermediaries between the pigment particles and the non-absorbent substrate, and also between successive ink layers. They create a stable interface that prevents bleeding and ensures proper adhesion of multiple ink layers, enabling high-quality polychrome printing

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If conventional aqueous inkjet ink is used on non-absorbent substrates, then the printing process is straightforward, but the printed image lacks durability and resistance to wiping

Engineering Contradiction:
Improveprinting process simplicityVSAvoidprinted image durability
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The inkjet ink is formulated with binding agents (polyurethane dispersion, acrylic polymer) and fixing agents (calcium salts, zinc salts) that are applied simultaneously with the pigment. These components work together to create a durable, wipe-resistant printed image directly during the printing process, eliminating the need for separate primer or varnish application steps while maintaining process simplicity

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The inkjet ink is formulated as a composite system combining pigment particles, binding agents (polyurethane dispersion, acrylic polymer), fixing agents (calcium salts, zinc salts), and surfactants. This composite formulation creates a durable, wipe-resistant printed image that maintains both ease of operation and high strength/durability

Inventive Principle:
Principle #40Composite materials

4Productivity

If aqueous inkjet ink is stored at elevated temperatures, then the printing machine can operate efficiently, but the ink may become unstable and lose its advantageous properties

Engineering Contradiction:
Improveprinting machine efficiencyVSAvoidink stability
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The inkjet ink is formulated with specific components (binding agents, fixing agents, surfactants) and maintained within specific parameter ranges (pH 6-9, viscosity 5-50 mPa·s) that ensure stability at elevated temperatures. The fixing agents (calcium salts, zinc salts) and binding agents work together to maintain ink composition stability during printing operations at higher temperatures, preventing degradation and ensuring consistent printing quality

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The surfactants and binding agents act as intermediaries that stabilize the pigment particles and prevent aggregation during storage at elevated temperatures. These components maintain the ink's advantageous properties (adhesion, fixation, flow characteristics) even when the printing machine operates at higher temperatures for improved productivity

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The ink composition ensures excellent adhesion and stability, enabling high-quality images on non-absorbent substrates with resistance to wiping and allows further inks to be applied without bleeding, even at elevated temperatures.

Implementation Method 1

a low concentration of a calcium salt as a fixing agent

Methodology Applied
Scientific EffectFixation: Adsorption

Implementation Method 2

a polyurethane binder with low acid value, which adheres well to non-absorbent substrates

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 3

a dispersing agent with low acid value

Methodology Applied
Scientific EffectDispersion: Dispersion (of waves)

Implementation Method 4

maintains stability at elevated temperatures

Methodology Applied
Scientific EffectThermal stability: Thermal Expansion

Data Source

PatentUS12565592B2Aqueous inkjet ink for non-absorbent printing substrates and printing process
Publication Date: 2026.03.03 HEIDELBERGER DRUCKMASCHINEN AG

AI summary

An inkjet ink includes pigment, dispersing agent, fixing agent, binder and water. The binder is selected from polyurethanes of a low acid value, the dispersing agent has a low acid value, and the fixing agent is a multivalent calcium salt used in a low concentration. The inkjet ink is easy to apply by using commercial inkjet printing presses, has high storage stability, adheres to surfaces that do not absorb water, exhibits high resistance to wiping and is very advantageously capable of being overprinted by other water-based inkjet inks. A printing process is also provided.